Method for detecting and diagnosing epithelial cancer

ABSTRACT

A method for detecting epithelial cancer includes generating a real-time video image of the locus of potential cancerous sites on the epithelium. The real-time video image is displayed on a television monitor screen. The real-time video image on the monitor is examined to locate suspected cancerous sites and the results of such examination are recorded.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This Application is a Division of my co-pending U.S.A.application Ser. No. 09/262,555, filed Mar. 4, 1999, which was aContinuation-in-Part of U.S.A. application Ser. No. 08/553,377, filedFeb. 22, 1996, which is a national stage application, filed under 35U.S.C. §371, derived from corresponding International ApplicationPCT/US94/01918 (WIPO Publication WO05/22279), filed Feb. 16, 1994.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to methods for detecting and diagnosingepithelial cancer.

[0004] More particularly, the invention relates to a cancer detectionmethod employing video technology for real-time examination of potentialcancerous sites on the epithelium, combined with comparison of adigitized image of a suspect site with digitized images of knowncancerous and non-cancerous sites, to effect a diagnosis of the suspectsites.

[0005] In another aspect, the invention relates to real-timevideographic examination techniques in combination with in vivo tissuestaining techniques and with digitized image techniques for thediagnosis of epithelial cancer.

[0006] In an even further and still more particular respect, theinvention relates to cancer detection/diagnosis techniques in whichvideographic records of the visual image of a suspected cancer site onthe epithelium are compared with a real-time videographic image of thesuspected site which is made at a later time.

[0007] In a further aspect the invention relates to cancerdetection/diagnosis techniques in which digitized videographic images ofa suspected cancerous site on the epithelium is compared with digitizedimages in a data base containing images of both cancerous andnon-cancerous epithelial lesions.

[0008] 2. Description of Related Art

[0009] Visual examination of epithelial tissue to detect cancerous orpre-cancerous tissue is known. In vivo examination of suspectedcancerous sites using standard photographs, magnification by anoperating microscope (stomatoscopy) and color photomicrographs for thedetection of oral cancer was described in the article by Shedd et al.,American Journal of Surgery, Volum 110, pages 631 et seq. (October1965).

[0010] Dental televison cameras which facilitate visualization of theoral cavity are also well known. See, e.g., the U.S. Pat. Nos. 4,260,376to Litel; 4,195,626 to Lemmey and 5,251,023 to Cooper. Apparatus andmethods for recording in vivo holograms and for reconstructing suchrecorded holograms for later display on a television monitor weredescribed by Bjelkhagen, et al. in U.S. Pat. No. 5,014,709.

[0011] The use of biological stains for in vivo selective delineation ofcancerous and pre-cancerous tissue is also well known. See, e.g., U.S.Pat. No. 4,321,251 to Mashberg and the article by Nibel (Journal ofAmerican Dental Association, Volume 35, pages 801 et seq. (June 1964)).Shedd, supra, discloses the use of selective tissue staining techniquesin combination with stomoatoscopy.

[0012] Cancer of the oral mucosa is one of the leading terminal diseasescausing thousands of deaths annually in the United States alone. Oralcancers occur at various places in the oral cavity, including the floorof the mouth, the anterior pillars, on the pallet and on the bottom andthe dorsum of the tongue. Most oral cancers are curable by surgicalexcision if detected early enough. However, the difficulty ofvisualizing the various intraoral epithelial surfaces makes it difficultto detect oral cancers in the very early stages. It is particularlydifficult to detect pre-cancerous sites in the oral cavity, because ofthe difficulty in visualizing the physically remote oral epitheliumcoupled with the confusingly similar appearance of precancerous tissueswith tissue having other, non-cancerous conditions.

[0013] While video technology and equipment has been available for anumber of years which enables dental practitioners to visualizeintraoral tissue in order to facilitate conventional dental proceduresand while tissue staining techniques have been known for many yearswhich selectively stain and visually delineate cancerous epithelialtissue and plaque and while photographic, holographic and othertechniques have been known for recording visual images for laterexamination, such techniques have not been effectively employed toprovide straightforward real-time diagnostic visual examination of theintraoral epithelium for detection of oral cancers and pre-cancerousconditions.

[0014] It would be highly desirable to provide improved methods fordetecting epithelial cancers, particularly oral cancers.

[0015] It would also be advantageous to provide such methods which canbe effectively employed by general dental practitioners as a part ofroutine dental procedures or “check-ups” or as an adjunct to routineperiodic dental office visits for plaque removal and the like. Suchimproved oral cancer detection methods could result in early detectionof oral cancer and timely therapy, saving many thousands of livesannually.

SUMMARY OF THE INVENTION

[0016] Accordingly, the principal object of the present invention is toprovide an improved method for early detection of epithelial cancer,particularly oral cancers, including single or multiple small or largesites.

[0017] Yet another object of the invention is to provide such improvedmethods which can be used effectively by general dental practitioners,with a minimum of additional training and expense, to provide routineoral cancer screening services as an adjunct to routine dentalprocedures and examinations.

[0018] Still another object of the invention is to provide oral cancerscreening techniques which permit real-time examination of remotelylocated epithelial tissues in the oral cavity, which are difficult toexamine by conventional visual examination techniques.

[0019] Still another and further object of the invention is to providereal-time cancer detection techniques which, nevertheless, provide apermanent record of the results of such an examination, so as to permitcomparative examination of the present image of a suspected cancer sitewith images of the same site made at an earlier time.

[0020] A still further object of the invention is to provide anepithelial cancer detection and delineation method which provides avisual record for later reference during therapy, e.g., to aid inexcision surgery.

[0021] Yet another object of the invention is to provide a method fordetermining whether a suspected cancerous site on the epithelium iscancerous or non-cancerous, employing a comparison of a digitizedvideographic image of the suspected site with digitized images knowncancerous and non-cancerous epithelial lesions.

BRIEF DESCRIPTION OF THE DRAWING

[0022] Those and other, further and more specific objects and advantagesof the invention will be apparent to those skilled in the art from thefollowing detailed description thereof, taken in conjunction with thedrawing in which:

[0023]FIG. 1 is a flow sheet illustrating various embodiments of themethod of the present invention, and the best mode presently known forthe practice thereof.

[0024] Briefly, in accordance with the invention, I provide a method fordetecting epithelial cancer which includes the steps of generating videosignals which represent the real-time image of the locus of potentialcancerous sites on the epithelium, displaying this real-time image on atelevision monitor screen, visually examining the displayed image tolocate suspected cancerous sites, digitizing said real-time image of asuspected cancerous site and comparing the digitized image of thesuspected site with digitized images in a data base of images of knowncancerous and non-cancerous oral epithelial lesions. In a furtherpreferred embodiment of the invention, the method also includes applyinga biological stain to the epithelium, to selectively cancerous tissue.Other aspects of the best mode presently contemplated for practicing thepresent invention are disclosed in connection with the description ofFIG. 1, set forth below.

[0025] The drawing is presented for purposes of illustrating thepreferred practice of the invention, but is not intended as a limitationon the scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Referring to FIG. 1, according to my method a conventional dentalvideo camera is used to make a preliminary scan 10 of the tissue whichis the locus of potential cancerous sites on the epithelium. Forexample, a suitable video camera for use in accordance with my inventionis disclosed in the patent to Cooper et al. U.S. Pat. No. 5,241,025. Thevideo image 11 from the scan 10 may be subjected to electronic imageprocessing 12 (as indicated by the arrow 11 a) or the image 11 can bedirectly utilized as indicated by the arrow 11 b. Either the processedimage 12 a or the unprocessed image 11 b is then displayed for visualexamination 13 on a television monitor screen. If such visualexamination 13 definitively reveals a cancerous site, as indicated bythe arrow 13 a, this may be directly employed to effect a diagnosis 14.

[0027] On the other hand, if the visual examination 13 does not yield adefinitive diagnosis 14, but indicates suspect cancerous sites (asindicated by the arrow 13 b), then a selective stain is applied 15 tothe suspect sites and a second video scan 16 of the stained sites ismade. For example, such selective stain compositions are included indiagnostic kits which are commercially available in certain countriesunder the trademark “ORASCAN”, “ORASCREEN” and “ORATEST”. The image fromthe second scan 16 is then either subjected to image processing asindicated by the arrow 16 a or the unprocessed image 16 b is displayedon a television monitor for visual examination 13. The visualexamination of the processed or unprocessed image from the second scan16 may also lead directly to a diagnosis 14.

[0028] The video signals representing the images formed by either thefirst scan 10 or the second scan 16, processed or unprocessed, arerecorded 17, for example by a conventional video recorder, as indicatedby the arrows 17 a, 17 b and 17 c and the resultant records 17 d arestored 18 for future reference.

[0029] Any of the visual examinations 13 may be facilitated bycomparisons 19 of the real-time image 13 c and a previously recordedstored image 18 a of the same site to facilitate diagnosis 14, asindicated by the arrow 19 a. Similarly, a visual examination 13 mayindicate the necessity or desirability of a biopsy 21 as indicated bythe arrow 13 d, to confirm the diagnosis 14 as indicated by the arrow 21a. If the diagnosis 14 indicates that therapy is required as indicatedby the arrow 14 a, the therapy, for example, surgical excision can befacilitated, as indicated by the arrow 19 b by a comparison 19 of thereal-time image 13 c with a stored image 18 a or by direct reference tothe stored image 18 b.

[0030] Alternatively, in accordance with the presently preferredembodiment of the invention a real-time video image 11, which isdetermined by the visual examination 13 to be a suspected canceroussite, can be digitized, as indicated by the arrow 13 e and the digitizedimage 22 of the suspected cancerous site is then compared 24 with a database of digitized images of known cancerous and non-cancerous oralepithelial lesions, to determine with greater accuracy by shape, surfacetexture and topography whether the suspected site is cancerous ornon-cancerous. The results 23 b of the comparison may, therefore,directly yield a diagnosis 14 or, if the results are still questionable,the compared site 23 a is subjected to conventional biopsy 21. Theresults of which 21 a yield a diagnosis 14.

[0031] As used herein, the term “cancerous site” is intended to includeboth cancerous and precancerous tissues. The cancerous tissue may be insitu carcinomas or early-invasive carcinomas and the precancerousconditions include dysplastic tissues or lesions and neoplastic tissuesor lesions as distinguished from the normal squamous epithelium.

[0032] The term “image processing” includes any of the known electronicimage intensification techniques, including as for example, digitalfiltering, contrast enhancement, frequency analysis, 3-D rotation,digital magnification, threshold analysis and the like.

Having described my invention in such terms as to enable those skilledin the art to understand and practice it and having identified thepresently preferred embodiments and best mode thereof, I claim:
 1. Amethod for detecting epithelial cancer, comprising: (a) generating videosignals which represent a first image of the locus of a potentialcancerous site on the epithelium; (b) digitizing said first image toproduce a digitized first image; and (c) comparing said digitized firstimage with a data base of digitized images of known cancerous epitheliallesions.
 2. The method of claim 1, wherein said data base also includesdigitized images of non-cancerous epithelial lesions.
 3. The method ofclaim 1, which includes the step of applying a biological stain, whichselectively stains cancerous and precancerous tissue, to said locus onthe epithelium, before video signals representing said first image aregenerated.